Simplify the following expression: $k = \dfrac{2h - 6}{2g + 2f} - \dfrac{6f}{2g + 2f}$ You can assume $f,g,h \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{2h - 6 - (6f)}{2g + 2f}$ $k = \dfrac{2h - 6 - 6f}{2g + 2f}$ The numerator and denominator have a common factor of $2$, so we can simplify $k = \dfrac{h - 3 - 3f}{g + f}$